I use pin 2 & 3 ( interrupt ) on UNO . On MEGA2560 , I can not use those pins because the 3.5" mcufriend is using the pins . Can I instead use the pins 18 to 20 ? These are also interrupt pins or are they not compatible pins with the UNO?
Marco
Of course, you can. UNO and Mega have different pin mapping for alternative I/O functions. While the UNO has INT0, INT1 on pins 2, 3, the Mega has INT0 on 21, INT1 on 20, INT2 on 19 and INT3 on 18. See the schematics for UNO and Mega. It is there. Also, I can recommend to find very useful pinout diagrams by pighixxx on the net.